Stacker for continuous form sheets

ABSTRACT

Apparatus for folding and stacking continuous form sheet in which the sheets are driven into the stacker at a predetermined speed and a continuous chain member is mounted extending into the path of the continuous form sheets. The chain member is driven at a speed greater than the predetermined speed and the combined action of the chain member and a curved guide member positioned adjacent the input path forces the continuous form sheets to fanfold into the stacking compartment.

[ STACKER FOR CONTINUOUS FORM SHEETS [75] Inventor: William R. Bartz, San Jose, Calif.

[73] Assignee: International Business Machines Corporation, Armonk, NY.

22 Filed: Sept. 5, 1972 21 Appl. No.2 285,982

[ Apr. 30, 1974 Novick 270/73 X Miller 270/79 X Primary ExaminerRobert W. Michell Assistant ExaminerL. R. Oremland Attorney, Agent, or Firm-Otto Schmid, Jr.

[571 ABSTRACT Apparatus for folding and stacking continuous form sheet in which the sheets are driven into the stacker at 52 US. Cl 270/61 F, 226/71 a predetermined speed and a continuous chain [51] Int. Cl.'. B65h 45/101 ber is mounted extending into the P of the Continu- [58] Field f S h 270/39, 40, 1 F, 73 79; ous form sheets. The chain member is driven at 2 226/171 111 speed greater than the predetermined speed and the combined action of the chain member and a curved [56] References Cit d guide member positioned adjacent the input path UNITED STATES PATENTS forces the continuous form sheets to fanfold into the 3,627,304 12 1971 Reeder et al. 270 61 F Stackmg compartment 3,178.172 4/1965 Lettan 270/79 11 Claims, 3 Drawing Figures CONTROL UNIT PATENTEUAPR30 m4 shin 2 0f 2 IIIIIIIII rlllilllllflllnlllllll moss STACKER FOR CONTINUOUS FORM SHEETS BACKGROUND OF THE INVENTION DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1 there is shown web handling ap- This invention relates generally to web handling hanparatus embodying the folding and Stacking apparatus dling apparatus and more particularly to improved apparatus for use in high speed printer applications for folding and stacking continuous paper forms in fanfold configuration.

A major problem exists in reliably refolding paper that has been processed in a machine such as the high speed printer. This difficulty iscaused by the loss of memory at the crease in the continuous form paper due to stresses caused by processing the sheet through the printer. In addition, the aerodynamic forces become a problem at high operating speeds since an air cushion forms adjacent the sheet and there is insuffi cient time at the operating speed for the air cushion to escape and permit the form to flatten on the stack. Various approaches have been used in the prior art and these approaches have been successful in folding continuous form sheets at lower operating speeds. How ever, these stackers have not been suitable for also stacking sheets that have been burst in the machine from the continuous form input.

SUMMARY OF THE INVENTION It is therefore the primary object of this invention to provide a stacker for reliably stacking the output from a high speed printer either in fanfold form or in individual sheets which have been burst in the machine from the continuous form input.

It is an additional object of the invention to provide a stacker which will reliably stack a wide range of weights of paper.

It is a further object of this invention to provide a stacker which will reliably stack a wide range of paper lengths.

These and other objects are achieved by a folding and stacking device which comprises drive means for feeding continuous form sheets of material into a stacking'compartment bounded by first and second guide means at a predetermined speed along an angular path having a continuous chain means extending into the path with the chain means being driven at a speed greater than the predetermined speed so that the continuous form sheets of material are forced to take a continuous curvature when extending toward the first guide means and a curved guide member coacting with the chain means forces the continuous form sheets of material to take a continuous curvature when extending toward the second guide means.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view of the stacking apparatus comprising the invention with some parts cut away to more clearly show the novel structure;

FIG. 2 is a front view of an alternate embodiment of the stacking apparatus embodying the invention with some parts cut away to more clearly show the novel structure; I

FIG. 3 is a left side view of the embodiment of the apparatus shown in FIG. 2 with some parts cut away to more clearly show the novel structure.

for continuous forms of the present invention. The components of the apparatus are fixed between spaced mounting plates 35, 37 which have been omitted from FIGS. 1 and 2 to more clearly show the structure. The apparatus comprises input feeding means 10 which is actuated by suitable drive means to drive the continuous form web 6 into the stacking compartment 16 of the stacking and folding apparatus at a predetermined speed. The drive means comprises drive motor 26 and suitable means such as belts or gears (shown dotted in the drawings) for coupling this power source to drive various components in the machine. Electrical signals to control motor 26 and other components in the printer and stacker are provided by control unit 25. Control unit may comprise wired control circuits or the control signals may be provided by the processor of an associated data processing machine if desired.

Stacking compartment 16 is formed by a stacking platform 18, a first guide means 20 and a second guide means 22 arranged so that the sheets 8 of the continuous forms web 6 are placed on the stacking platform between the first and the second guide means. Overlying the stacking compartment 16 is a chain means 12. Chain means 12 is continuously driven in an enclosed path by suitable driving means 14 at a speed greater than the predetermined speed at which the input continuous form web is driven. Chain means 12 is positioned to frictionally engage the input continuous form web so that the web is positioned and driven by the chain means.

In the embodiment shown, chain means 12 comprises a plurality of continuous chain members driven by suitable means 14 and supported by a guide member 64 and idler members 66 and 68. The chain members hang in an arcuate path extending into the entry path of the continuous forms web at an angle approximately 30 to the horizontal. Chain means 12 may comprise any suitable member which produces the effect of weight on the continuous forms without impeding the motion in the desired direction. Rather, the motion in the desired direction is enhanced due to the frictional engagement with the continuous forms.

A curved guide member 24 positioned closely adjacent to input driving means 10 and extending adjacent chain means 12 forces the incoming web to assume a curved position which gives the web substantial lateral stiffness so that the web does not buckle across its width. The chain means 12 exerts sufficient force on the continuous form web so that the individual sheets are forced to take a favorable position for reliable stacking in a fanfold configuration.

To achieve reliable folding and stacking of the web, it has been found that this can best be accomplished by keeping the individual sheets 8 of the web under posijacent to chain means 12 which frictionally engages the leading edge of the first sheet 8a of continuous forms web 6 (see FIG. 1) thereby driving the leading edge of the web at an angle toward stacking platform 18. The leading edge of the sheet is continuously urged toward guide means 20 by engagement of the sheet by chain means 12. This is accomplished due to the frictional engagement of the web by chain means 12 and the fact that chain means 12 is being driven at a speed greater than the speed at which the web is being driven into the stacking compartment. in a specific embodiment that functioned as described, a plurality of ladder chains was used and the chains were driven about ten per cent faster than the input form speed. This action causes the sheet to continue until the leading edge of the sheet 8a abuts guide means 20. At this time the perforation between the sheets 8a and 8b is just being driven past curved guide means 24 and the action of this guide member and the drag caused by the sheet being stacked, causes the weakened part between sheets 8 to break over, thereby extending the fold toward guide means 22 (see dotted position in H0. 1). As the feeding of continuous form web 6 continues the second sheet 8b is forced to take a curved position with the loop being propagated toward guide means 20 as the trailing edge of the first sheet is settling adjacent guide means 22. This continues until a point is reached (see full line position in FIG. 1) close to guide means 20 at which point the loop in the second sheet becomes sufficiently small so that the weight of the chain means 12 and the fact that the chain is being driven at a speed greater than the input speed of the continuous form web causes the end of the second sheet to be snapped over toward guide means 20. At this point the operation becomes repetitive with the succeeding sheets 8 of the continuous form web 6 being laid down on stacking platform 18 in fanfold configuration.

The apparatus is also operable to stack sheets that have been burst from the continuous form Web. In the case of sheet input, the operation is as described above for sheet 8a until this sheet abuts guide means 20. The second sheet enters the stacking compartment as the trailing edge of sheet 8a is settling and the curvature produced in the sheets insures that the second sheet will be directed toward guide means 20 due to engagement with. chain means 12 and the fact that chain means 12 is being driven at a faster rate than the sheet.

Thus, it can be seen that the reliable folding and stacking operation provided by applicants invention is due to the combination of the action of the chain means, the curved guide means and the drive means which provides a higher speed drive to the chain means than to the continuous form web input drive which results in the individual sheets being forced to assume a particular curvature which is continuously changing as the continuous form web is stacked in fanfold configuration in the stacking compartment.

There are many sizes of sheets which can be obtained in the continuous forms web. It is desirable that a folding and stacking apparatus for a computer output printer be designed to stack all standard sizes of forms that are available. The embodiment of the apparatus shown in FIG. 2'is designed to stack all standard sizes of forms. In this embodiment first guide means 20 is selectively adjustable so that the distance between guide means 20' and 22 can be set to accommodate any desired size of form. Guide means 20' is selectively movable by adjusting means 30 which is operable to set the distance between guide means 22 and guide means 20' to a selected form size. Adjusting means 30 comprises suitably rotating shaft means 32 to position guide means 20' to accommodate the selected form size. The rotation of shaft 32 can be accomplished manually by an operator if desired, or can be driven by a suitable clutched drive from motor 26 in which the clutch is actuated by an appropriate control signal from the printer control unit. Guide means 20' comprises a suitable support member 34 which extends across the stacking compartment and member 34 is supportedv for movement relative to guide means 22. The movement is provided by rotating shaft 32 and spur gear 36, which is fixed to shaft 32, acting with rack member 38 to position support member 34. If desired, detent means can be provided along rack member 38'to designate each of the standard form lengths. A plurality of guide members 40 extend from support member 34 into recesses in stacking platform 18 to provide a stop to position the leading edge of the continuous form web. To insure that the curvature of chain means 12 maintains a desirable configuration, an extended ramp portion 42 of support member 34 is provided. Lateral guides 44 are provided to maintain the spacing of chain means 12 as the chains move over the ramp portion 42 and maintain the proper curvature in chain members 12 in the stacking area so that reliable stacking results.

Thus, it can be seen that there is provided apparatus which is adjustable either manually by operator control or through suitable control circuits from the printer control unit to select a particular-form'length for folding and stacking in stacking compartment 16.

it is also desirable to provide apparatus that will reliably stack a wide variety of weights of paper in the continuous form web. ln extremely light weight paper, the mechanical strength of the form is very slight, even when the form is curved as previously described. As an aid to reliably stacking the forms and particularly the lighter weightsof paper, it is sometimes desirable to provide apparatus to aid in placement of the trailing edge of the form. In the embodiment shown, this function is provided by flexible belt means 50 which is continuously driven adjacent the trailing edge of the stacked sheets so that the form is aided in its downward movement to remove the trapped air between succeeding forms without the form buckling between perforations. Belt means 50 comprise a plurality of belts having flexible fingers projecting into the stacker area to aid in stacking the continuous form web. The belts are driven continuously by driven pulley 54 moving downward against the folded edges of the form. The lower run of the belts is around idler member 56 so mounted that belts 52 are pivotable toward and away from the stack of forms as shown by dotted lines in the drawing.

In a specific embodiment that worked well, belts 52 were driven at a speed about one-third of the input form speed.

To further aid in the stacking, the stacking platform 18, on which the forms are stacked, is movable relative to guide means 20 and 22 so that the distance between the top of the stack of forms and the chain means can be accurately maintained. This is accomplished by stack height sensing means comprising a light source 58 mounted at one side of the stacker near fixed guide means 22. On the opposite side of the stacker a photoelectric cell 60 is mounted in position to receive light from source 58. When the height of the stacked forms reaches a predetermined height, the light from source 58 does not reach photocell 60. A signal is generated as a result and the this signal is used to energize a suitable drive means to lower the height of stacking platform 18. One suitable drive means is a reversible electric motor (not shown) which is coupled to drive lead screw 62 directly. This drive continues until the light from source 58 again impinges on photocell 60. Limit switches are provided to prevent stacking platform 18 from being driven higher or lower than pre-set limits.

While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in the form and details may be made therein without departing from the spirit and scope of the invention.

What is claimed is:

l. A mechanism to fanfold transversely perforated elongated sheets of material comprising:

a stacking compartment comprising a stacking platform and first and second upstanding guide means;

means for feeding the material into said stacking compartment along a path at an angle to said stacking platform toward said first guide means at a predetermined speed;

continuous chain means having a certain mass and friction characteristic so that said chain means frictionally engages said material and means to mount the chain means for movement around a continuous path having an arcuate portion extending into the path of said material;

means for driving said chain means so that said arcuate portion is driven toward said first guide means at a speed exceeding said predetermined speed, and

a curved guide member positioned adjacent to said chain means and having a surface which guides said material, said surface being convex in the direction of said material and extending from said chain means toward said second guide means whereby said material is forced to fanfold into said stacking compartment by the combined action of said chain means and said curved guide member.

2. The apparatus according to claim 1 wherein the distance between said first and second upstanding guide members is adjustable to a plurality of predetermined distances so that a plurality of lengths of sheets can be folded and stacked.

3. The apparatus according to claim 2 additionally comprising means movable with said first guide member to adjust the arcuate path of said chain means as said distance between said guide members is adjusted.

4. The apparatus according to claim 1 additionally comprising a continuous flexible belt member having flexible fingers extending into said stacking compartment adjacent said second guide member; and

means to drive said belt member in a continuous path so that said flexible fingers tend to compact the trailing edges of folded sheets stacked in said stack ing compartment.

5. The apparatus according to claim 4 wherein the distance between said first and second upstanding guide members is adjustable to a plurality of predetermined distances so that a plurality of lengths of sheets can be folded and stacked.

6. The apparatus according to claim 5 additionally comprising means movable with said first guide member to adjust the arcuate path of said chain means as said distance between said guide members is adjusted.

7. The apparatus according to claim 1 additionally comprising means for sensing the height of the stack of sheets on said stacking platform; and

drive means for adjusting the height of said stack and means in response to a signal from said height sens ing means to energize said drive means to maintain the stack at a predetermined height.

8. The apparatus according to claim 7 wherein the distance between said first and second upstanding guide members is adjustable to a plurality of predetermined distances so that a plurality of lengths of sheets can be folded and stacked.

9. The apparatus according to claim 8 additionally comprising means movable with said first guide member to adjust the arcuate path of said chain means as said distance between said guide members is adjusted.

10. The apparatus according to claim 9 additionally comprising a continuous flexible belt member having flexible fingers extending into said stacking compartment adjacent said second guide member, and

means to drive said belt member in a continuous path so that said flexible fingers tend to compact the trailing edges of folded sheets stacked in said stacking compartment.

11. The apparatus according to claim 7 additionally comprising a continuous flexible belt member having flexible fingers extending into said stacking compartment adjacent said second guide member, and

means to drive said belt member in a continuous path so that said flexible fingers tend to compact the trailing edges of folded sheets stacked in said stacking compartment. 

1. A mechanism to fanfold transversely perforated elongated sheets of material comprising: a stacking compartment comprising a stacking platform and first and second upstanding guide means; means for feeding the material into said stacking compartment along a path at an angle to said stacking platform toward said first guide means at a predetermined speed; continuous chain means having a certain mass and friction characteristic so that said chain means frictionally engages said material and means to mount the chain means for movement around a continuous path having an arcuate portion extending into the path of said material; means for driving said chain meanS so that said arcuate portion is driven toward said first guide means at a speed exceeding said predetermined speed, and a curved guide member positioned adjacent to said chain means and having a surface which guides said material, said surface being convex in the direction of said material and extending from said chain means toward said second guide means whereby said material is forced to fanfold into said stacking compartment by the combined action of said chain means and said curved guide member.
 2. The apparatus according to claim 1 wherein the distance between said first and second upstanding guide members is adjustable to a plurality of predetermined distances so that a plurality of lengths of sheets can be folded and stacked.
 3. The apparatus according to claim 2 additionally comprising means movable with said first guide member to adjust the arcuate path of said chain means as said distance between said guide members is adjusted.
 4. The apparatus according to claim 1 additionally comprising a continuous flexible belt member having flexible fingers extending into said stacking compartment adjacent said second guide member; and means to drive said belt member in a continuous path so that said flexible fingers tend to compact the trailing edges of folded sheets stacked in said stacking compartment.
 5. The apparatus according to claim 4 wherein the distance between said first and second upstanding guide members is adjustable to a plurality of predetermined distances so that a plurality of lengths of sheets can be folded and stacked.
 6. The apparatus according to claim 5 additionally comprising means movable with said first guide member to adjust the arcuate path of said chain means as said distance between said guide members is adjusted.
 7. The apparatus according to claim 1 additionally comprising means for sensing the height of the stack of sheets on said stacking platform; and drive means for adjusting the height of said stack and means in response to a signal from said height sensing means to energize said drive means to maintain the stack at a predetermined height.
 8. The apparatus according to claim 7 wherein the distance between said first and second upstanding guide members is adjustable to a plurality of predetermined distances so that a plurality of lengths of sheets can be folded and stacked.
 9. The apparatus according to claim 8 additionally comprising means movable with said first guide member to adjust the arcuate path of said chain means as said distance between said guide members is adjusted.
 10. The apparatus according to claim 9 additionally comprising a continuous flexible belt member having flexible fingers extending into said stacking compartment adjacent said second guide member, and means to drive said belt member in a continuous path so that said flexible fingers tend to compact the trailing edges of folded sheets stacked in said stacking compartment.
 11. The apparatus according to claim 7 additionally comprising a continuous flexible belt member having flexible fingers extending into said stacking compartment adjacent said second guide member, and means to drive said belt member in a continuous path so that said flexible fingers tend to compact the trailing edges of folded sheets stacked in said stacking compartment. 